[Treatment of post-orthodontic white spot lesions]. / Behandeling van postorthodontische wittevleklaesies.

White spot lesions are early demineralisations and therefore constitute an impairment to healthy enamel. The emergence of white spot lesions is one of the main risks of damage during orthodontic treatment with fixed appliances. White spot lesions may partially recover, but will remain visible in most cases. The treatment for post-orthodontic white spot lesions is a step-by-step strategy. Treatment is aimed at remineralising the affected enamel, without hyper-mineralising the surface layer. Subsequently, treatment of post-orthodontic white spot lesions is aimed at reducing their visibility. Such treatment options focus on minimally invasive treatment techniques, before choosing an invasive treatment. More randomised clinical trials are needed to substantiate the evidence-based treatment of post-orthodontic white spot lesions. Clinical practice guidelines are being developed for the care and treatment of orthodontic white spot lesions.

Effects of casein phosphopeptide amorphous calcium fluoride phosphate paste on white spot lesions and dental plaque after orthodontic treatment: a 3-month follow-up.

The effects of casein phosphopeptide amorphous calcium fluoride phosphate (CPP-ACFP) paste vs. control paste on the remineralization of white spot caries lesions and on plaque composition were tested in a double-blind prospective randomized clinical trial. Fifty-four orthodontic patients, with multiple white spot lesions observed upon the removal of fixed appliances, were followed up for 3 months. Subjects were included and randomly assigned to either CPP-ACFP paste or control paste, for use supplementary to their normal oral hygiene. Caries regression was assessed on quantitative light-induced fluorescence (QLF) images captured directly after debonding and 6 and 12 wk thereafter. The total counts and proportions of aciduric bacteria, Streptococcus mutans, and Lactobacillus spp. were measured in plaque samples obtained just before debonding, and 6 and 12 wk afterwards. A significant decrease in fluorescence loss was found with respect to baseline for both groups and no difference was found between groups. The size of the lesion area did not change significantly over time or between the groups. The percentages of aciduric bacteria and of S. mutans decreased from 47.4 to 38.1% and from 9.6 to 6.6%, respectively. No differences were found between groups. We observed no clinical advantage for use of the CPP-ACFP paste supplementary to normal oral hygiene over the time span of 12 wk.

Biomechanical considerations in the design of patient-specific fixation plates for the distal radius.

Use of patient-specific fixation plates is promising in corrective osteotomy of the distal radius. So far, custom plates were mostly shaped to closely fit onto the bone surface and ensure accurate positioning of bone segments, however, without considering the biomechanical needs for bone healing. In this study, we investigated how custom plates can be optimized to stimulate callus formation under daily loading conditions. We calculated implant stress distributions, axial screw forces, and interfragmentary strains via finite element analysis (FEA) and compared these parameters for a corrective distal radius osteotomy model fixated by standard and custom plates. We then evaluated these parameters in a modified custom plate design with alternative screw configuration, plate size, and thickness on 5 radii models. Compared to initial design, in the modified custom plate, the maximum stress was reduced, especially under torsional load (- 31%). Under bending load, implants with 1.9-mm thickness induced an average strain (median = 2.14%, IQR = 0.2) in the recommended range (2-10%) to promote callus formation. Optimizing the plate shape, width, and thickness in order to keep the fixation stable while guaranteeing sufficient strain to enhance callus formation can be considered as a design criteria for future, less invasive, custom distal radius plates. Graphical abstract ᅟ.

Implementation of a semiautomatic method to design patient-specific instruments for corrective osteotomy of the radius.

PURPOSE: 3D-printed patient-specific instruments (PSIs), such as surgical guides and implants, show great promise for accurate navigation in surgical correction of post-traumatic deformities of the distal radius. However, existing costs of computer-aided design and manufacturing process prevent everyday surgical use. In this paper, we propose an innovative semiautomatic methodology to streamline the PSIs design. METHODS: The new method was implemented as an extension of our existing 3D planning software. It facilitates the design of a regular and smooth implant and a companion guide starting from a user-selected surface on the affected bone. We evaluated the software by designing PSIs starting from preoperative virtual 3D plans of five patients previously treated at our institute for corrective osteotomy. We repeated the design for the same cases also with commercially available software, with and without dedicated customization. We measured design time and tracked user activity during the design process of implants, guides and subsequent modifications. RESULTS: All the designed shapes were considered valid. Median design times ([Formula: see text]) were reduced for implants (([Formula: see text]) = 2.2 min) and guides (([Formula: see text]) = 1.0 min) compared to the standard (([Formula: see text]) = 13 min and ([Formula: see text]) = 8 min) and the partially customized (([Formula: see text]) = 6.5 min and ([Formula: see text]) = 6.0 min) commercially available alternatives. Mouse and keyboard activities were reduced (median count of strokes and clicks during implant design (([Formula: see text]) = 53, and guide design (([Formula: see text]) = 27) compared to using standard software (([Formula: see text]) = 559 and ([Formula: see text]) = 380) and customized commercial software (([Formula: see text]) = 217 and ([Formula: see text]) = 180). CONCLUSION: Our software solution efficiently streamlines the design of PSIs for distal radius malunion. It represents a first step in making 3D-printed PSIs technology more accessible.

Lack of platelet factor-3 activation after incubation of platelet-rich plasma with kaolin in the rat.

Stypven times, measured in rat platelet-rich plasma (P.R.P.) after incubation with kaolin, did not shorten as incubation proceeded, thus reflecting the lack of development of platelet factor-3 (PF3) availability in this test system. Repeated freezing and thawing of P.R.P. or aggregation with collegan did result in PF-3 availability. Aggregation and PF-3 availability were inhibited by the compound VK774. These findings add another aspect to the list of species differences in platelet function.

Pharmacokinetics of two human menopausal gonadotrophin preparations after single intravenous administration during pituitary suppression.

A randomized study was performed in nine healthy women, to investigate pharmacokinetic parameters and bioequivalence of two human menopausal gonadotrophin preparations after i.v. administration. Endogenous gonadotrophin activity was suppressed by triptorelin administration. Humegon and Pergonal (225 IU of each) were injected i.v. in a cross-over way with an interval of 1 week. Blood samples were collected frequently and serum concentrations of follicle stimulating hormone (FSH), luteinizing hormone (LH), specific LH, and human chorionic gonadotrophin (HCG) were determined by fluoroimmunoassays assays. Serum LH bioactivity was measured by an in-vitro bioassay. The area under curve (AUC) and half-life of FSH were respectively 431.5 IU h/l and 22.20 h for Humegon, and 402.6 IU h/l and 21.33 h for Pergonal. For both preparations, the (total) LH immunoactivity and in-vitro bioactivity of serum LH were very similar, and appeared to be a composite of specific LH and HCG activity. The AUC data of specific LH were 17.50 IU h/l for Humegon and 21.79 IU h/l for Pergonal respectively. The AUC and half-life of HCG were 153.7 IU h/l and 14.80 h for Humegon, and 134.1 IU h/l and 12.11 h for Pergonal. The two preparations were bioequivalent with respect to FSH and HCG immunoreactivity. Bioequivalence could not be proven for LH activity because of the small number of subjects.